Hybrid Car – More Fun with Less Gas

Hey do you know your car's alternator only outputs 7-10% while it's running? - Page 8

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Posted by StickThatInYourPipeAndSmokeIt on August 8, 2009, 2:29 pm
 
wrote:


sustainable voltage.


  Please go away, you less than even the worst layman IDIOT!

Posted by Archimedes' Lever on August 8, 2009, 3:22 pm
 
wrote:


 The old generators in cars required high rpms to function efficiently.

 Alternators were designed and incorporated into cars specifically
because they do NOT require a high rpm to have efficient output, so you
are wrong about the 2k rpm minimum.

 Also, idiot, and wind turbine (ALL in fact) gear the blade speed up to
drive the alternator at a higher rpm.  It would be no problem to convert
blade rotation into a higher rpm shaft drive.

  I do agree with you though that richardson is a dopey dumbfuck.

Posted by Johnny B Good on August 8, 2009, 5:07 pm
 

 Not quite right. Alternators could use a much stronger rotating field
assembly with an anti-burst co-axial wound field coil which allowed them
to be geared to run twice as fast as the old dynamo designs they
supplanted. The much higher revs at idling speed meant they were able to
produce a useful (though not full) output when the engine was idling.


 Whilst that is true, the step up gearing introduces undesired
additional transmission loss which gets worse the higher the speed step
up ratio used.

 Ideally, an alternator designed to match the direct drive speed should
be chosen where practical. Obviously, for a home built solution, such a
compromise might represent the most pragmatic choice.

--
Regards, John.

 Please remove the "ohggcyht" before replying.
The address has been munged to reject Spam-bots.


Posted by clare on August 9, 2009, 1:59 am
 On Sat, 08 Aug 2009 08:22:52 -0700, Archimedes' Lever


He is NOT wrong. At curb idle the average alternator is not capable of
producing nameplate power. Curb idle of 750RPM spins most alternators
at roughly 2100 RPM due to the pulley ratio. The BIG advantage of
alternators is that belted at 3:1, at 6000 rmp engine speed (18000 rpm
alternator speed) the rotor does not unwind itself - there is no
catastrophic separation of the commutator, and all the other nasty
stuff that happened to generators at high speeds.

And most definitely not all wind turbines gear up the alternator. Most
of the BIG commercial units do have a gearbox - in many cases
incorporating a governor.

Something like that - yes.

Posted by Archimedes' Lever on August 9, 2009, 2:35 am
 On Sat, 08 Aug 2009 21:59:15 -0400, clare@snyder.on.ca wrote:


 No shit.  Did you spend your entire life coming to that conclusion, or
did someone just hit you upside da haed with a common sense stick?

  It certainly does not require 2000 rpms either.

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